An Auxiliary Solid Tire.
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An Alternative to the Spare Wheel for Taxicabs and Light Vans.
'Ube Blackwell Him Co., whose works are ill the Midlands, recently introduced to the notice of the manager of a large provincial motorcab garage the speciality which bears the name that is indicated in the title of the company. So taken was this official with the advantages that were claimed for the device that, seemingly anxious to spread information with regard to it, he, with characteristic enterprise, at once suggested to the proprietors that they should "ask Tax Costsmeetar. Monist to have a look at it," and that, if the " C.M." thought it to be a good thing, to suggest that a description of it be inserted in its columns.
Promptly thereupon came a request from the Blackwell people to this office that we should, at an early opportunity, see the rim under working conditions. The intervention of the Manchester Show, and the stress of many business engagements on both sides, prevented an inspection's being made for a few weeks; then came deplorable weather, which resulted in further delay. An owner of a private ear, however, who had been so convinced that Blackwell rims were " the right goods " that he had had a set of them fitted to the wheels of his own machine, came to the rescue of the makers and offered to place his car at the disposal of a representative of this journal in order that a suitable test might he made without further delays In the end, braving the considerable discomfort of adverse climatic conditions, a party, one day last week, set out to make an exhaustive trial of what proved to be a very-simple device indeed.
We reproduce herewith two photographs. which will do more to illustrate the nature of the innovation than would columns of letterpress. It will be seen that the Blackwell rim itself consists of a lightly-designed, pressed-steel rim, of which an integral part is a continuous skeleton form of flange. The rim holds. in Clincher fashion, a length of light-section solid tire, and the flange serves to bolt this complete arrangement direct to the fellne of the wheel. An inspection of the nhotographs will show that, these auxiliary rims are bolted permanently into position on the insides of the wheels. The miter diameter of each small assistant tire, if we may call it so, is approximately 3 in. less than that of the fully-inflated pneumatic tire belonging to the wheel to which the auxiliary rim is attached. This difference in dimensions gives ample clearance from the ground when the pneumatic tire is fully inflated. Directly the latter, however, becomes deflated to any noticeable extent, the small solid tire comes into contact with the ground and assumes the functions that are normally performed by the main road wheel.
A puncture, therefore, when these rims are hued, does not necessitate the unshipping of a spare wheel, nor the ascertainment that the tire on such a component is fully inflated and in good order. What is of the utmost importance is that it is impossible for a driver knowingly to run on a deflated tire, to the extensive damage of both cover and tube, as is so often the case when ordinary pneumatics are in use solely. The Blackwell device appeared to a representative of this journal, at first sight, to be an excellent one, as much on account of its simplicity as anything. It was, therefore, promptly decided to put it through a test which should be comparable to the conditions to which it would be exposed in taxicab service in London. The private owner who kindly placed his car at our disposal for this purpose always runs it on " Sealomatic " tubes, but it was decided that it would be unfair to endeavour to secure data as to the effect upon ordinary tubes as the result of running with a special nonpuncturable tube like the " Sealomatic." Ordinary tubes therefore were fitted, and a test. was then run over a circuitous route from East to West London, a route which embraced all classes of road service, from the worst of pot-holed macadam to badly-graded granite setts. Chalk marks were first of all placed round the inner solid tires, and the pressures in the pneumatics were carefully noted ; these latter proved to be 80 lb. for the back tires and 60 lb. for the front.. A. fast drive over a variety of bad surfaces, together with a number of sudden traffic checks and the negotiation of many sharp corners, failed to reveal any inconvenience which might. have been exnected to have arisen from the bumping of the car down on to the hard
solid tires. Subsequent careful inspection of the chalk marks on these auxiliary fittings showed that the inner tires had undoubtedly been in contact with the road in many places, but that the chalk was only erased in a few. This small "humping " support may have a value.
A back wheel was next selected, and the chauffeur was instructed to let the air out of the pneumatic, so that the whole weight should be taken, so far as one back wheel was concerned, by the auxiliary solid tire only. The run was then continued, over all classes of road. to one of the western suburbs, and care was taken, so far as was possible, to approximate the conditions of taxicab service. Immediately upon arrival at thdestination. which involved a matter of two or three miles of running, the inner
tube which had been deflated was exposed and removed from the rim, and a careful examination was made of it. It was found not to be even "hand warm," and, although it was a tire that had evidently had quite an exciting history in the past, as judged by the number of patches and sleeves it, possessed, it showed no sign whatever of damage from the run under deflated conditions. It was subsequently re-inserted in the rim, and pumped up to full pressure; it ran back under a heavy load quite satisfactorily. The cover, also, after minute inspection, showed no sign of damage. The automatic manner in which the deflated tire is relieved of responsibility, and the Lick of necessity to carry a spare wheel ot any description and to fit it, are advantages that are so obvious as to need no more than passing mention now.
There is no doubt that the Blackwell rim is a useful conception, and it should appeal to all users of light industrial vehicles, which it is found advisable to mount upon pneumatics. So far as its applicatiors to taxicab wheels is concerned, its fitting upon the inside of the main wheel obviously imposes less stress upon the axle than does an externallysecured wheel of the detachable type, and possessors of motorcabs with light front axles, who have experienced trouble in this respect in the past, will be particularly interested in the Blackwell device. The inner position of the auxiliary solid seriously reduces the range of lock of the steering wheels, and that circumstance will require careful consideration by the makers in connection with taxicabs which have to comply with Scotland Yard's 25-ft. turning circle ; in the Provinces this restriction is not so insistent.
We have recently drawn attention to the additional facility which the use of spare wheels has afforded to taxicab drivers who are by way of being dishOnest. The ease with which the taximeter-driving mechanism can he interfered with by a change of road wheels is now clearly understood. To those proprietors who have apprehensions on this score, as well as to others who are disinclined to lock up money by carrying spare tires, we commend the Blackwell rim as a simple and useful device.